1. Field of the Invention
The present invention relates to an image blur correction device correcting an image blur caused by vibration or the like during photographing, a lens barrel having the image blur correction device, and an imaging apparatus such as a digital still camera or video camera having the lens barrel.
2. Description of the Related Art
In recent years, performance of imaging apparatuses such as digital still cameras and video cameras has been remarkably improved, and thus still images and moving images may be easily captured by everyone with high image quality and high performance. Such improvement in performance of imaging apparatuses is largely due to improvement in performance of lenses, solid-state imaging devices (such as CCD image sensors and CMOS image sensors) and image processing circuits.
However, no matter how much the performance of lenses, solid-state imaging devices or the like is improved, a high resolution screen blurs and thus a captured image blurs when hands supporting a camera (imaging apparatus) tremble or shake. Therefore, some relatively expensive cameras have an image blur correction device mounted and correcting an image blur caused by shake or the like during photographing. However, image blur correction may be essentially needed not in high-end models for professional use but rather in popular models used by a majority of the public having only a little photographing experience.
Generally, cameras (imaging apparatuses) are demanded to be reduced in size and weight and are preferable to be light and easily carried. However, image blur correction devices of the related art are relatively large. Therefore, when the image blur correction device of the related art is mounted on a camera main body, the lens barrel and the camera are large as a whole, contrary to a demand for reduction in size and weight. In addition, an image blur correction device of the related art may need a large number of components and is significantly expensive due to an increase in the number of components, disadvantageously.
Japanese Unexamined Patent Application Publication No. 2000-258813 discloses an example of an image blur correction device of the related art. Japanese Unexamined Patent Application Publication No. 2000-258813 discloses an image blur correction device used for an optical device such as a video camera. The image blur correction device disclosed in Japanese Unexamined Patent Application Publication No. 2000-258813 is an image blur correction device correcting an image blur by moving part of a photographing lens into a plane perpendicular to an optical axis. The image blur correction device includes a lens holding frame, a first guide section, a second guide section, a first driving section, a second driving section and a position detection section. The lens holding frame holds a correction lens. The first guide section guides movement of the lens holding frame in a first direction in a plane perpendicular to the optical axis. The second guide section guides movement of the lens holding frame in a second direction perpendicular to the first direction. The first driving section drives the lens holding frame in the first direction. The second driving section drives the lens holding frame in the second direction. The position detection section detects a position of the correction lens. The first guide section and part of the second driving section, or the second guide section and part of the first driving section, are provided in positions overlapping each other in an optical axis direction.
According to the image blur correction device disclosed in Japanese Unexamined Patent Application Publication No. 2000-258813, it is expected that the correction device may be reduced in width and height (see paragraph [0032]), for example.
Japanese Unexamined Patent Application Publication No. 2007-156352 discloses another example of an image blur correction device of the related art. Japanese Unexamined Patent Application Publication No. 2007-156352 discloses a lens device having an image blur correction device correcting an image blur caused by vibration or the like during photographing. The lens device disclosed in Japanese Unexamined Patent Application Publication No. 2007-156352 includes: an image blur correction device; and a lens barrel to which the image blur correction device is attached. The image blur correction device has: a lens holding frame holding a correction lens; a first driving section moving the lens holding frame in a first direction perpendicular to an optical axis direction of the correction lens; and a second driving section moving the lens holding frame in a second direction perpendicular to the optical axis direction and also perpendicular to the first direction. The image blur correction device displaces an optical axis of the correction lens held in the image blur correction device from a center of the lens barrel, and is placed so that the first driving section and the second driving section generate thrust in a direction forming an angle of about 45° with a line connecting the optical axis of the correction lens to the center of the lens barrel.
According to the lens device disclosed in Japanese Unexamined Patent Application Publication No. 2007-156352, it is expected that the image blur correction device is efficiently placed in the lens barrel, making it possible to reduce the diameter of the lens barrel and reduce the lens device and the whole imaging apparatus in size (see paragraph [0015]).